|Merchants fueled a thriving middle class.|
The poem is called Wynnere and Wastoure, and refers to Winners (who earn money) and Wasters (who are extravagant with money). The narrator, while walking on a sunny day, falls asleep by a stream and has a dream-vision. (This is a common way to begin an allegory.) In the dream, Winner and Waster each lead an army. Just before their battle begins, a messenger arrives who summons them before the king, who will listen to their argument and resolve their issues definitively.
This he fails to do. After listening to the arguments of the two, the king gives an ambiguous judgment, condemning each as unbalanced practices but endorsing both as necessary actions in society—although the king does point out that Winner will never be able to keep up with Waster. Thornton's manuscript breaks off at line 503, so any conclusion after his judgment is lost to us.
Internal evidence in the poem suggests a date of composition prior to 1370: it mentions a Chief Justice, William Shareshull, who died in 1370. That would place the composition in the reign of Edward III, and it is generally accepted by scholars that the king of the poem is meant to represent Edward, who himself would have had constant dealing with "wasting" because of his expenses on wars and living well, and with the "winners" of a growing and increasingly wealthy middle class.